For an AC analysis, DC sources are short circuit (voltage source) or open circuit (current source), respectively. Accordingly, for a DC analysis, AC sources are short circuit (voltage source) or open circuit (current source), respectively. As these sources have no internal resistance, they are noisefree.
The MNA matrix of a current source is (with short circuit current flowing into node 1 and out of node 2):
(9.141) |
The MNA matrix of a voltage source is (with open circuit voltage across node 1 to node 2):
(9.142) |
The MNA matrix of a power source is (with internal resistance and available power ):
(9.143) |
The factor "8" is because of:
The noise current correlation matrix of a power source equals the one of a resistor with resistance .
All voltage sources (AC and DC) are short circuits and therefore their S-parameter matrix equals the one of the DC block. All current sources are open circuits and therefore their S-parameter matrix equals the one of the DC feed.